This invention relates generally to the detection of flaws, checks and like imperfections, in the neck portion of a bottle. More specifically, the invention concerns bottle inspecting apparatus for detection of a wide range of both horizontal and vertical imperfections in the neck portion of a bottle by a continuously rotating sensing head.
In the past, there has been a need to inspect the neck and threaded mouth portions of glass bottles to be used as a container for foodstuffs and the like. The existence of checks, cracks and imperfections has been the cause of failure of the bottle or the bottle neck portion when the bottles are subsequently filled with a liquid for distribution in the channels of commerce. Typically, the loss or failure of a bottle constitutes a loss of the contents thereof as well as establishing an injury potential for consumers, employees and the like.
One characteristic of bottle imperfections which has been utilized in the past for bottle inspection devices is the tendency of the imperfections to reflect incident light. Accordingly, some previously known bottle check detectors have detected reflected light as an indication of the presence of bottle checks.
Many bottle inspecting devices heretofore known have employed some means for rotating individual bottles below a stationary inspecting head to optically indicate the presence or absence of imperfections. Such known devices, however, are not well adapted to handle bottles of various volumetric capacity and cross-sectional configuration: e.g., half-gallon and quart sizes; round, rectangular and square bottles. In addition, the rotation of the bottle beneath an inspecting head does not lend itself to the high speed inspection of bottles, i.e., a rate of a hundred bottles or more per minute.
Other known bottle inspection devices raise each bottle to an inspection station which rotates with respect to the bottle to perform an optical inspection. See, for example, U.S. Pat. No. 3,479,514, issued to Kidwell on Nov. 18, 1969. Such devices, however, do not inspect for both vertical and horizontal cracks with a single inspection head. Accordingly, a plurality of inspection devices are necessary to completely inspect a bottle for both types of cracks.
Still other bottle inspection devices carry bottles by a conveyor to an inspection station where they are detained by a laterally swinging arm that holds them in position below a rotating inspection head. See Rottmann Pat. Nos. 3,245,533, and 3,328,000 issued on Apr. 12, 1966 and June 27, 1967 respectively. The rotating inspection heads of these known devices are adapted only to determine the presence of generally horizontal cracks and do not effectively indicate the presence of vertical cracks which are equally deleterious.
Ordinarily, no synchronization is used between bottle detaining mechanisms and rotating inspection heads in the known devices, thereby making destructive contact possible between the rotating head and bottles being positioned for inspection. Other difficulties with the known rotating head devices include the slowness in the inspection process and a single pass inspection. Speed of inspection is important since it permits fewer inspection stations to examine a given number of bottles in a given period of time. A multi-pass inspection is desirable to insure that randomly placed imperfections near the beginning or end of the inspection cycle are detected.
Devices are also known which utilize a rotating head to inspect the surface of a bottle continuously moving therebelow. See, for example, the Calhoun et al patent 3,349,906, issued Oct. 31, 1967. These devices, however, are not adapted to determine the presence or absence of imperfections in the bottle material itself and are also subject to error induced by spurious reflections from bottles being advanced into the inspection position below the rotating head.
Thus, the need continues to exist for a high speed bottle inspection device which is capable of rapidly and effectively determining the presence of bottle imperfections which may be in both generally horizontal and generally vertical planes.